package vn.info.vietnaminfo.lazylist;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Collections;
import java.util.Map;
import java.util.WeakHashMap;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import vn.info.vietnaminfo.R;
import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.util.Log;
import android.widget.ImageView;

public class ImageLoader {

	MemoryCache memoryCache=new MemoryCache();
	FileCache fileCache;
	private Map<ImageView, String> imageViews=Collections.synchronizedMap(new WeakHashMap<ImageView, String>());
	ExecutorService executorService; 

	public ImageLoader(Context context){
		fileCache=new FileCache(context);
		executorService=Executors.newFixedThreadPool(5);
	}

	final int stub_id = R.drawable.empty_bg;
	public void DisplayImage(String url, ImageView imageView)
	{
		Log.v("vo day truoc dung ko", "urrl = "+url);
		imageViews.put(imageView, url);
		Bitmap bitmap=memoryCache.get(url);
		Log.v("vo day truoc dung ko", "chu gi nua bitmap = "+bitmap);
		if(bitmap!=null)
		{
			Log.v("vo day truoc dung ko", "chu gi nua");
			imageView.setImageBitmap(bitmap);
		}
		else
		{
			Log.v("vo day sau dung ko", "dung roi");
			queuePhoto(url, imageView);
			imageView.setImageResource(stub_id);
		}
	}

	private void queuePhoto(String url, ImageView imageView)
	{
		PhotoToLoad p=new PhotoToLoad(url, imageView);
		executorService.submit(new PhotosLoader(p));
	}

	private Bitmap getBitmap(String url) 
	{
		File f=fileCache.getFile(url);

		//from SD cache
		Bitmap b = decodeFile(f);
		if(b!=null)
			return b;

		//from web
		try {
			Bitmap bitmap=null;
			URL imageUrl = new URL(url);
			HttpURLConnection conn = (HttpURLConnection)imageUrl.openConnection();
			conn.setConnectTimeout(30000);
			conn.setReadTimeout(30000);
			conn.setInstanceFollowRedirects(true);
			InputStream is=conn.getInputStream();
			OutputStream os = new FileOutputStream(f);
			Utils.CopyStream(is, os);
			os.close();
			bitmap = decodeFile(f);
			return bitmap;
		} catch (Exception ex){
			ex.printStackTrace();
			return null;
		}
	}

	private Bitmap decodeFile(File f){
		try {
			//decode image size
			BitmapFactory.Options o = new BitmapFactory.Options();
			// will results in a much smaller image than the original
			o.inSampleSize=8; //try to decrease decoded image
			o.inPurgeable=true; //if necessary purge pixels into disk
			o.inScaled=true; //sc
			BitmapFactory.decodeStream(new FileInputStream(f),null,o);

			//Find the correct scale value. It should be the power of 2.
			final int REQUIRED_SIZE=70;
			int width_tmp=o.outWidth, height_tmp=o.outHeight;
			int scale=1;
			while(true){
				if(width_tmp/2<REQUIRED_SIZE || height_tmp/2<REQUIRED_SIZE)
				{
					break;
				}
				width_tmp/=2;
				height_tmp/=2;

				scale*=2;
			}

			//decode with inSampleSize
			BitmapFactory.Options o2 = new BitmapFactory.Options();
			o2.inSampleSize=scale;
			return BitmapFactory.decodeStream(new FileInputStream(f), null, o2);
		} catch (FileNotFoundException e) {}
		return null;
	}

	//Task for the queue
	private class PhotoToLoad
	{
		public String url;
		public ImageView imageView;
		public PhotoToLoad(String u, ImageView i){
			url=u; 
			imageView=i;
		}
	}

	class PhotosLoader implements Runnable {
		PhotoToLoad photoToLoad;
		PhotosLoader(PhotoToLoad photoToLoad){
			this.photoToLoad=photoToLoad;
		}

		@Override
		public void run() {
			if(imageViewReused(photoToLoad))
				return;
			Bitmap bmp=getBitmap(photoToLoad.url);
			memoryCache.put(photoToLoad.url, bmp);
			if(imageViewReused(photoToLoad))
				return;
			BitmapDisplayer bd=new BitmapDisplayer(bmp, photoToLoad);
			Activity a=(Activity)photoToLoad.imageView.getContext();
			a.runOnUiThread(bd);
		}
	}

	boolean imageViewReused(PhotoToLoad photoToLoad){
		String tag=imageViews.get(photoToLoad.imageView);
		if(tag==null || !tag.equals(photoToLoad.url))
			return true;
		return false;
	}

	//Used to display bitmap in the UI thread
	class BitmapDisplayer implements Runnable
	{
		Bitmap bitmap;
		PhotoToLoad photoToLoad;
		public BitmapDisplayer(Bitmap b, PhotoToLoad p){bitmap=b;photoToLoad=p;}
		public void run()
		{
			if(imageViewReused(photoToLoad))
				return;
			if(bitmap!=null)
				photoToLoad.imageView.setImageBitmap(bitmap);
			else
				photoToLoad.imageView.setImageResource(stub_id);
		}
	}

	public void clearCache() {
		memoryCache.clear();
		fileCache.clear();
	}

}
